BUN/Creatinine Ratio
The BUN/creatinine ratio is a calculated number: your blood urea nitrogen divided by your serum creatinine. It compares two kidney-related waste products.
Because BUN and creatinine respond differently to hydration, blood flow, and diet, their ratio can help your clinician tell apart possible causes when one or both are abnormal, such as dehydration versus a kidney-based issue.
A higher ratio can point toward dehydration, reduced blood flow to the kidneys, a high-protein diet, or bleeding in the digestive tract. It's a clue rather than a diagnosis and is always read alongside the individual values.
A lower ratio can occur with a low-protein diet, liver conditions, or overhydration, and often isn't concerning by itself.
The ratio is interpreted only in context with BUN, creatinine, and your symptoms; there's no single target to aim for. Your clinician can explain what yours suggests.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.